Hi lynnj53 and welcome. Happy Halloween.
A bulls-eye rash looks like ... well ... a bulls-eye (concentric red circles).
A bulls-eye rash is a sign of Lyme disease, hands down. You can't get any more positive than a bulls-eye rash.
My rash was not a bulls-eye. Mine was a red oval, about 6" in diameter, and very very itchy!
If you have a bulls-eye or other rash, it's a really good idea to take a photo of it with a coin or a ruler for scale. A photo will be helpful in terms of getting a diagnosis and treatment for Lyme.
Do you have any other symptoms? Were you bitten recently? Are you seeing an LLMD (Lyme Literate Medical Doctor)? Are you currently being treated?
Peace and health to you,